The present invention relates to a vibrator appliance, and particularly to one useful for a peritoneal dialysis (PD) treatment. The invention also relates to a dialysis method and particularly to one utilizing the novel vibrator appliance.
Peritoneal dialysis (PD) is a medical treatment administered when there is insufficient functioning of the kidneys. It is performed by inserting a sterile plastic catheter into the abdominal cavity of the subject and instilling a dialysate solution to irrigate the peritoneum such that solutes transfer across the peritoneal membrane into the dialysate solution from the blood in the mesentery capillary network. This treatment does not require a machine, such as in hemodialysis, but does require much longer periods of time in order to achieve solute removal comparable to that of intermittent hemodialysis. Such a treatment is commonly performed in an ambulatory manner as a CAPD (Continuous Ambulatory Pertioneal Dialysis) treatment.
CAPD is usually performed in four 6-hour sessions during each 24-hour period. In each session, the dialysate solution is instilled into the abdominal cavity of the subject and permitted to dwell therein for a period of six hours, following which the dialysate solution is drained, and a fresh dialysate solution is instilled. This relatively large number of sessions greatly disturbs the daily routine of the subject. It also increases the risk of infection.
Various studies have been conducted on the application of mechanical vibrations for improving the efficiency of waste removal by PD (pertioneal dialysis); see J.Rudoy et al. Nephron 46:364-366 (1987); Levit et al. Kidney International, Vol. 35, pp. 1145-1150 (1989); and Utsunomia-T et al., Nippon-Jinzo-Gakkai-Shi; January 1995 37(1):24-8. The Rudoy et al. publication (1987) describes an improvement in peritoneal transfer on human subjects when subjected to mechanical vibrations at a frequency of 24 Hz by a vibrator held by the patient perpendicular to the patient""s abdomen; the Levitt et al. publication (1989) describes studies of the effects produced on the rate of peritoneal transfer in rats by shaking the rats; and the Japanese publication (1995) describes studies on the rate of peritoneal transfer in rats by vibrating the abdominal wall at the rate of 80 Hz.
Objects of the present invention are to provide a vibrator appliance particularly useful in peritoneal dialysis, and also an improved method of peritoneal dialysis. The apparatus and method of the present invention are particularly useful for CAPD, but may also be used for other PD treatments, such as APD (Automated Peritoneal Dialysis), and CCPD (Continuous Cycling Peritoneal Dialysis) usually administered at home during the nighttime.
According to one aspect of the present invention, there is provided an appliance to enhance the rate of removal of solutes during a peritoneal dialysis treatment of a subject, comprising: a holder to be applied to the subject; and at least one vibrator device carried by the holder at a location thereof to engage the subject""s abdomen and to apply localized, inwardly-directed mechanical vibrations thereto at a frequency of 1-15 Hz.
As will be described more particularly below, surprisingly good results were produced when the vibrator device applies the mechanical vibrations at a frequency of 2-6 Hz,
In the preferred embodiments of the invention described below, there are two vibrator devices carried by the holder at locations to engage the opposite sides of the subject""s abdomen and oriented to apply inwardly-directed mechanical vibrations towards the central region of the subject""s abdominal cavity.
According to another aspect of the invention, there is provided a method of administering a peritoneal dialysis treatment to a subject comprising a vibration session including: instilling a dialysate solution into the peritoneal cavity of the subject; applying external localized mechanical vibrations to the front side of the abdomen of the subject at a frequency of 1-15 Hz and an amplitude of 1-20 mm; and draining the dialysate solution from the subject""s abdominal cavity. As indicated above, and as will be more fully described below, surprisingly good results were obtained when the mechanical vibrations were applied, at a frequency of 2-6 Hz and at a amplitude of 5-10 mm, especially when two vibrator heads were used engaging the front side of the subject""s abdomen on opposite sides of its center line and oriented to direct mechanical vibrations to the central region of the subject""s abdominal cavity.
Thus, it was found that applying the vibrations at a frequency of over 15 Hz did not permit the vibrations to propagate deeply into the body cavity, and therefore the 24 Hz frequency mentioned in the J.Rudoy et al. publication cited above only produced a limited improvement in the peritoneal dialysis treatment. It was also found that applying the vibrations at a frequency of less than 1 Hz also produced very limited benefits. Surprisingly good results were found in the frequency range of 2-6 Hz, which produced an improvement of up to 150% in the solute removal rate, as compared to an improvement of about 30-40% when applying the mechanical vibrations at a frequency of 24 Hz as described in the J.Rudoy et al. publication.
The optimum rate, preferably within the 2-6 Hz range, can be determined emperically for each subject, according to the size, build and weight of the subject.
The vibrational amplitudes are preferably in the range of 1-20 mm, best results having been obtained with amplitudes of 5-10 mm. These amplitudes are inversely related to the frequency; that is, at the lower end of the above frequency range the vibrational amplitudes would be at the higher end of the amplitude range, and vice versa. Preferably, the combination of amplitude and frequency should be just below the level producing significant pain or discomfort to the subject, e.g., at the second limit of ISO Standard 2631.
Further features and advantages of the invention will be apparent from the description below.